hold on just to get this straight, do both the twins like haruhi?? または just one??

No Hikaru is in luv with her in マンガ kaoru just acts like he does so hikaru can realize it. kaoru values his "brothrly'' relationship mor and hikaru just thinks hes her ''toy''. kinda like how tamaki likes her exept he thinks of it as a daoughtr/fatr relationship. did tht help? and no i didnt get tht from wikipeia i rly do read the manga

I think both twins like her

Well (in the アニメ atleast), I think Hikaru likes her もっと見る than Kaoru but Kaoru pushes Hikaru into hanging out with her more.
So they both like but Hikaru like her もっと見る and Kaora tries to get them together because he is trying to be nice to his brother.